In recent years, there have been remarkable developments in the field of mobile wireless communications and now wireless communications can be performed regardless of time and place. As disclosed in Patent Literature 1 (Japanese Unexamined Patent Application Publication No. 2012-213100, titled “Telephone System, Mounting Device, Terminal Device, Switching Device, and Device Connection Method for Telephone System”) and Patent Literature 2 (Japanese Unexamined Patent Application Publication No. 2013-257227, titled “Automatic Response Apparatus, Automatic Response Relay Apparatus, Automatic Response Communication System, Automatic Response Method, and Automatic Response Program”, for example, even when a user is walking or moving by a moving body such as a vehicle, wireless communication via a base station or a mobile wireless communication relay apparatus (e.g., a mobile router) can be achieved.
Such a wireless communication relay apparatus called a mobile router or the like wirelessly relays a voice call or a Voice over Internet Protocol (VoIP) call from a base station to a wireless communication terminal. Since such a wireless communication relay apparatus alone does not have a function of communicating with a caller, the wireless communication relay apparatus alone cannot perform a voice call or a VoIP call even when it receives a phone call from the caller via the base station. When the wireless communication relay apparatus receives the phone call from the caller via the base station, the wireless communication relay apparatus notifies the wireless communication terminal, which is the relay destination, that there is an incoming call. Then the wireless communication terminal that has received the notification regarding the incoming call from the wireless communication relay apparatus picks up (goes off hook), responds to the incoming call, and starts communication via the base station and the wireless communication relay apparatus.